Conventionally, a rotating electric machine is known to have a rotor and an armature. The rotor is a permanent-magnet type rotor and disposed on an inner side of the armature. For example, JP-2012-85445A discloses a rotor for a rotating electric machine. The rotor is an interior-magnet type rotor having a magnet mounted inside a rotor core. The rotor has a covering portion located on both side surfaces of the magnet in an axial direction. The covering portion is integrally formed with a fixed portion fixed to a rotor shaft, and restricts the magnet from moving in the axial direction.
A surface-magnet type rotor having a magnet on a surface of a rotor core may be employed as the rotor. In this case, a tubular portion is disposed to cover a radially-outer surface of the magnet so that the tubular portion restricts the magnet from being scattered by centrifugal force.
The covering portion of the rotor disclosed in JP-2012-85445A is fixed to only the fixed portion, so a space is produced between the rotor core and the covering portion. Therefore, when the magnet is broken while in use, fragments of the magnets may come out through the space. Moreover, when the covering portion has an extending portion to bias the magnet in the axial direction, a reaction force from the biased magnet is applied to the covering portion. In this case, the space between the rotor core and the covering portion may be broaden, and bigger fragments of the magnet may come out through the space.
When the surface-magnet type rotor is employed, an outer peripheral part of the tubular portion is inwardly crimped onto the covering portion. By crimping the outer peripheral part of the tubular portion, a space may not be produced between the tubular portion and the covering portion. However, when the outer peripheral part of the tubular portion is plastically deformed, a deforming load is applied to the magnet in the axial direction through the covering portion, and the magnet may get broken.